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本文采用纳米Fe_3O_4颗粒作为磁性核心,先用四乙氧基硅烷、再用3-巯丙基三乙氧基硅烷和3-氨丙基三乙氧基硅烷修饰Fe_3O_4颗粒,形成表面带-NH_2和-SH的Fe_3O_4/SiO_2纳米颗粒,进一步通过-NH_2的静电吸附和Au-S键的作用将金纳米颗粒组装在Fe_3O_4/SiO_2表面,形成具有核壳结构的Fe_3O_4/SiO_2/Au金磁纳米颗粒,并用透射电子显微镜镜(TEM)、能量色散X射线光谱仪(EDX)、紫外可见分光光度计(UV-vis)等技术对金磁纳米颗粒进行了形貌观测及性质表征。利用Fe_3O_4/SiO_2/Au金磁纳米颗粒作为拉曼活性基底,用表面增强拉曼光谱仪对黄曲霉毒素B1(AFB1)进行直接快速检测,发现无外磁体浓缩的情况下AFB1的检测限大于10.0μg/m L,在外磁体浓缩金磁纳米颗粒的情况下检测限降低100倍(≤0.1μg/m L),检测线性范围0.1μg/m L~10.0μg/m L,检测的样品回收率为84.35%~91.98%,相对标准偏差在4.88%~9.90%之间。
In this paper, Fe_3O_4 nano-particles as the magnetic core, the first tetraethoxysilane, and then 3-mercaptopropyl triethoxysilane and 3-aminopropyl triethoxysilane modified Fe_3O_4 particles to form the surface with -NH_2 and -SH Fe_3O_4 / SiO_2nanoparticles, the gold nanoparticles were further assembled on the surface of Fe_3O_4 / SiO_2 by electrostatic adsorption of -NH_2 and Au-S bonds to form Fe_3O_4 / SiO_2 / Au gold nanoparticles with a core-shell structure, The morphology and properties of gold nanoparticles were characterized by TEM, EDX and UV-vis. Direct detection of aflatoxin B1 (AFB1) by surface-enhanced Raman spectroscopy using Fe 3 O 4 / SiO 2 / Au gold nanoparticles as the Raman-active substrate found that the detection limit of AFB1 was greater than 10.0 μg with no external magnet concentration / m L, the limit of detection (LOD) was reduced by 100 times (≤0.1 μg / mL) in the presence of magnetic nanoparticles and the linear range was from 0.1 μg / mL to 10.0 μg / mL with the recovery of 84.35 % ~ 91.98%, relative standard deviation between 4.88% ~ 9.90%.